The included WIFI on the new devices makes them an advertisers wet dream.

The devices can give feedback to the advertisers on the reach and effectiveness of the ads themselves. The ads would probably have click-through capabilities at some point. The advertisers would be able to know how long certain ads are really in view of a live person in addition to how many times the ads were actually visible. I am certain that the learned model from Internet Advertising and payment would easily apply to the usage in eBooks.